STATE PLANT BOARD
August 1952 E-844
United States Department of Agriculture
Agricultural Research Administration
Bureau of Entomology and Plant Quarantine
NOTES ON LYCTIDAE (COLEOPTERA)
By Ross H. Arnett, Jr.
Division of Insect Detection and Identification
That the family Lyctidae, the false powder-post beetles, is of
economic importance is indicated by the numerous times these small
beetles are encountered in various manufactured goods, such as ax and
hammer handles, baskets, and furniture, as well as in buildings and in
herbs and roots.
Recently two species, Lyctus prostomoides Gorham and L. impressa
Comolli, have come to my attention as intercepted and imported pests.
Although there is no evidence that they have become established in this
country, they may have gone unrecognized as " Lyctus sp." Another species
L. villosa Lesne, was sent in for identification recently, and from the
data accompanying the specimens, as well as from additional specimens
in the U. S. National Museum collection, it appears that this species may
have become established in this country, but has not yet been recorded in
the literature. Therefore, a few notes on the distinctive appearance of
these species, their hosts and distribution, may call attention to their
presence in this country, either in existing collections or in those made
in the future.
There is some controversy over the proper generic placing of the first
two species mentioned above. The current catalog (Lesne _7, pp. 14-16)
places them in the genus Trogoxylon LeConte (_5, p. 209). The validity of
the separation of this genus from Lyctus Fabricius (2, p. 502) is question-
able. LeConte's separation was on the basis of the structure of the
anterior tibiae (viz., anterior tibia with the outer apical angle not pro-
longed in Trogoxylon and prolonged in Lyctus) . This character has since
been shown not to be constant for the species which LeConte included in
the genus. In the original description of the genus the genotype of
Trogoxylon was designated as the species Xylotrogus parallelipipedus
Melsheimer (8, p. 112). This designation gives us a basis for a definition
of the genus. The group that LeConte considered as constituting this
genus corresponds roughly to Kraus's (_4, pp. 116-118) group of species of
Lyctus with confused pubescence and confused or somewhat striate elytral
punctation. These species may or may not form a natural group but these
characters are hardly sufficient for the erection of a separate genus,
particularly when the other genera placed in this family are so distinct
from the genus Lyctus in the broad sense. Therefore, I prefer to keep
the generic name Lyctus in the old sense to include Trogoxylon , at least
until more comprehensive work is done and it is demonstrated that other
characters, such as those of the larvae and male genitalia, show that
further division of Lyctus is necessary.
The following information should help in the recognition of the three
species mentioned above and summarizes their distribution. The host
data are from specimens in the U.S. National Museum collection.
Lyctus prostomoides Gorham
Lyctus prostomoides Gorham (J3, p. 212)
Type locality : El Tumbador, Guatemala.
Size 2.5-5 mm. Color reddish-brown. Head with a prominent
double tubercle over the base of the antennae; thorax widest in front,
lateral margins nearly straight, anterior and posterior angles acute,
punctures moderately large, dense, deeper than those of elytra; outer
apical angles of anterior tibiae moderately produced; elytral pubescence
confused, moderately long and dense, recumbent, fine, yellow in color,
punctures confused, shallow, moderately dense.
This species will key to "Section a2" in Kraus's key (4), but will fit
neither alternative in that couplet because the pronotum is broader than
long and the pubescence is fine and not bristling and the prosternum is
not distinctly punctate throughout.
Hosts: Lacquered tray, wooden crate, dry wood, bamboo, carved
wood, basket, furniture, stem of Sambucus sp., and dried herbs.
Distribution and interceptions : Panama: San Lorenzo (Champion);
Guatemala: San Geronimo, Purula, El Tumbador (Champion); ?Nicaragua:
Chontales (Janson); Mexico: Cordoba (Knab), Jalisco (Diquet), Guanajuato
(Salle), Cuernavaca (via Chicago, 111.), Guadalajara (via Nogales, Ariz.),
"Mexico" (via Brooklyn, N. Y.), "Mexico" (via New York, N.Y.),
"Mexico" (via Pittsburgh, Pa.), "Reared from elephant carved from
soft African wood purchased from London dealer in Persian goods"
(via Rochester, N.Y.).
Lyctus impressa Comolii
/Tyctusj7 /Tmpressa]?7 Comolii (J_, p. 40). (Publication not seen.)
Type locality: presumably Novocomi (Italy?)
- 3 -
Size 2.5-5 mm. Color reddish-brown. Head with a prominent double
tubercle over the base of the antenna and another prominent, single
tubercle over the eye; thorax widest in front, lateral margins nearly
straight, anterior and posterior angles acute, pronotum very coarsely
and densely punctate, punctures confluent, Y-shaped impression on the
disc, the arms of the Y extending from the anterior margin of the
pronotum, at the point where the lateral margins of the head meet the
prothorax, to the center of the pronotum, and the base of the Y extending
nearly to the posterior margin of the pronotum; elytral pubescence con-
fused, short, sparse, recumbent, fine, yellow in color; punctures on
elytra confused, shallow, moderately dense, elytra with variable, vague
This species is included in Kraus's key (4).
Hosts : Licorice root, dried roots, chair, umbrella handle.
Distribution and interceptions : "Central Europe, Syria, Barbary
Coast /AfricJ7 " (Lesne ]_, p. 15); Turkey (via New York, N. Y.); France
(via New York, N. Y. ); Mississippi (Hopkins, in Kraus 4_, p. 130; speci-
men in U. S. National Museum collection).
Lyctus villosa Lesne
Lyctus villosus Lesne (6^, p. 537).
Type locality : Mexico: Zacoalco (Jalisco).
Size 2-3.5 mm. Color reddish-brown. Entire body covered with
long, coarse, almost scalelike, semierect hairs which are broadened
apically; head without tubercles; thorax quadrate, sides parallel, but
slightly sinuate, anterior and posterior angles rounded, surface of
pronotum coarsely rugose-punctate, punctures confluent; elytra with
pubescence arranged in even, double rows, punctures in serial arrange-
ment between rows of pubescence.
This species will key to Lyctus linearis Goeze in Kraus's key
(_4, p. 120). L. villosa is separated from _L_. linearis by the coarse,
scalelike pubescence, which is fine and appressed in the latter species.
Hosts: Unidentified wood, furniture, cedar closet, medicinal herbs,
"Banak" wood, balsa wood, on banana, wood ceiling in house, woodwork
in church, oak flooring, cigar boxes, in Leucaena esculenta (Moc. and
Sesse) Benth. (Leguminosae).
Distribution and interceptions: Mexico: Zacoalco, Guadalajara
(Jalisco) (via Nogales, Ariz.), "Mexico" (via Binghamton, N. Y.),
Monterrey(via Laredo, Tex.), "Mexico" (via Laredo, Tex.), Mexico, D.F.
UNIVERSITY OF FLORIDA
I I II
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3 1262 09239 6380
Tepic, Nayarit (via Nogales, Ariz.); San Salvador: San Salvador; Costa
Rica: "Costa Rica" (via New York, N. Y.); Panama: "Panama" (via New
Orleans, La.); Dutch Guiana: "Dutch Guiana" (via Tampa, Fla., and
New York, N. Y.); Ecuador: "Ecuador" (via Tampa, Fla.); United States:
Redlands, Calif., Clemson College, S. C, Brooklyn, N. Y., Tucson,
(1) Comolli, A.
1837. De Coleopteris novis ac rarioribus minusve cognitis
provinciae Novocomi. 54 pp. Ticini, Fusi. /_Publication
(2) Fabricius, J.
1792. Entomologia systematica, v. 1, 538 pp.
(3) Gorham, H. S. •
1883. Malacodermata. Biologia Centrali-Americana. Insecta,
Coleoptera. v. 3, pt. 2, 372 pp. i3 pi.
(4) Kraus, E. J.
1911. A revision of the powder-post beetles of the family Lyctidae
of the United States and Europe. U.S. Dept. Agr. Bur.
Ent. Tech. Ser. No. 20, pt. 3, pp. 111-138. Includes
appendix by A. D. Hopkins, Notes on habits and distri-
bution with list of described species.
(5) LeConte, J. L.
1862. Classification of the Coleoptera of North America, Part I,
Smithsn. Inst. Misc. Collect., v. 26, 286 pp.
(6) Lesne, M. P.
1911. Notes sur les Coleopteres Terediles. /Paris/ Mus. Natl.
d'Hist. Nat. Bul.^ v. 17, pp. 534-538,
1938. Bostrychidae. Coleopterorum Catalogus. Pars 161, 84 pp.
(8) Melsheimer, F. E.
1846. Descriptions of new species of Coleoptera of the United
States. Acad. Nat. Sci. Phila. Proc. 2, pp. 98-118.